The first unofficial national flag, called the Grand Union or Continental Colours, was raised at the behest of Gen. George Washington near his headquarters outside Boston, Mass. The flag had 13 alternating red and white horizontal stripes and the British Union Flag (a predecessor of the Union Jack) in the upper left corner.

May

According to a popular story, George Washington and two other representatives from the Continental Congress called upon a Philadelphia seamstress, Betsy Ross, to ask her to make a new American flag. This version of events cannot be confirmed by historians, however. Although nobody knows for sure who designed the flag, it may have been Continental Congress member Francis Hopkinson.

The first official flag, also known as the Stars and Stripes or Old Glory, was approved by the Continental Congress: "Resolved, That the Flag of the United States be 13 stripes, alternate red and white; that the Union be 13 stars, white in a blue field, representing a new constellation." The resolution did not specify how the stars should be arranged, and so the layout varied.

Congress authorized the addition of two more stars and two more stripes to mark the admission of Vermont and Kentucky to the Union in 1791 and 1792, respectively. This 15-star, 15-stripe flag, which came into use after May 1795, was the "star-spangled banner" that inspired lawyer and poet Francis Scott Key.

As daylight broke, Francis Scott Key saw the American flag still flying over Fort McHenry, after it had been bombarded all night by the British. Inspired, he wrote a poem entitled "The Defense of Fort M'Henry," which was later set to music and renamed the "Star-Spangled Banner." Congress made it the official national anthem in 1931.

After five more states joined the Union, Congress passed legislation fixing the number of stripes at 13 and requiring that the number of stars equal the number of states. (Each new star was to be added on the 4th of July following the state's entry into the Union.)

After New Mexico and Arizona joined the Union on Jan. 6 and Feb. 14, respectively, the flag had 48 stars. On June 24, President William Howard Taft issued an executive order that established the proportions of the flag and set the arrangement of the stars in horizontal rows.

President Harry Truman signed an Act of Congress that requested that the president issue an annual proclamation calling for the observance of Flag Day and for the display of the flag on all federal government buildings.